S-adenosyl methionine is an enzymatic cofactor involved in methyl group transfers. It methylates targets, many of which are in the brain. It deactivates dopamine by methylating a hydroxy group on the catechol.

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... Neurotransmitters are chemicals that carry messages from nerve cells to other cells. Low levels of the neurotransmitters, dopamine, norepinephrine, and serotonin are associated with depression. SAM-e is known to raise levels of dopamine and norepinephrine in the brain, and it may also accelerate the production, uptake, and re-release of serotonin. Although possible additional antidepressant actions of SAM-e have not been confirmed, results of some studies suggest that SAM-e may increase the sensitivity of receptors that react to these neurotransmitters or improve the ability of neurotransmitters to attach to active receptors. All of these effects are thought to help relieve depression. ...
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S-Adenosyl methionine Chemical name S-Adenosyl-L-methionine Other n ...
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